Silicon carbide fibers are advantageously high in strength, modulus, heat-resistance and oxidation-resistance and therefore form a promising material as a structural material. Carbon fibers are difficult in wetting to metal, such as aluminium, and rather reactive and hence inferior to silicon carbide fibers as a reinforcing material for FRM (fiber reinforced metal). Consequently, various processes of preparing the silicon carbide fibers have been developed, including a process for preparing silicon carbide fibers by spinning and baking an organo-silicon polymer having carbon-silicon bond as a main backbone, and a process for preparing silicon carbide whiskers by means of chemical vapor deposition technique. The former is disadvantageous in that a complicated procedure of synthesis, spinning and baking of the organo-silicon polymer is needed, resulting in a high production cost. The latter process, on the other hand, has disadvantages of low productivity and poor yield, resulting also in a high production cost. In order to solve these problems, there has been developed a process for preparing silicon carbide fibers by thermally decomposing in a vapor phase the organo-silicon compound within a heating reaction zone containing fine particles of metal per se or metal compound as a seeding catalyst (Japanese Patent Application No. 113689/82). This process, however, is disadvantageous in the following operations:
(1) operation of seeding microfine metal particles onto a substrate, PA0 (2) operation of setting the substrate in a reactor, PA0 (3) operation of heating the reactor, PA0 (4) reacting operation of the organo-silicon compound in the vapor phase, PA0 (5) operation of cooling the reactor, and PA0 (6) operation of collecting the fibers from the reactor.
These operations result in a difficult process for continuous production. Further, in such process, the reaction proceeds only on a surface of the substrate, resulting in a poor yield and hence a high production cost.
Accordingly, a general object of the invention is to provide a continuous process for preparing fine fibers of carbon and silicon, which is high in productivity and possible to reduce the production cost.
Accordingly, a general object of the invention is to provide a continuous process for preparing fine fibers of carbon and silicon, which is high in productivity and possible to reduce the production cost.